A process of fabricating a semiconductor device includes applying a resist solution to a substrate to form a resist pattern, and in order to secure high throughput, in general, a plurality of liquid processing units are used. Also, as semiconductor devices are diversified, the types of resistor solutions increase, and accordingly, the number of application nozzles is increasing. Thus, there is a technique of configuring a nozzle unit by integrating a plurality of nozzles corresponding to a plurality of types of resistor solutions and using the nozzle unit for a plurality of liquid processing units universally.
In such a device, a nozzle not in use has a layered structure which includes an air layer, a solvent layer, and an air layer. The layered structure is formed to act as a so-called cover in order to prevent a resist solution at a front end portion of the nozzle from becoming dry. Further, in the coating process, when the nozzle starts to be used, such as when a lot of the substrate is changed or the like, a dummy dispensing is performed to release the layer structure, and then, the coating is performed with a new resist solution. However, when the coating of one lot is terminated, the nozzle (nozzle unit) is moved to a standby position, the layer structure of the used nozzle is formed, and dummy dispensing is performed on a separate nozzle used for a follow-up lot. Thus, when the lot of the substrate is changed, when the time the nozzle is kept in the standby position is lengthened, the initiation of coating is delayed although the substrate has been loaded within the liquid processing unit, thus generating an unnecessary preparation standby time.
In changing the nozzle, a coating method is known which is for processing a dummy dispense of a nozzle before terminating the discharge of resist solution by a nozzle which has been used before changing, instead of performing coating after changing the nozzle. However, since this method is available only when each nozzle can move between a position at which a resist solution is discharged to a substrate and a standby position at which dummy dispensing is performed, the method is based on a different precondition from the present disclosure which uses a common arm to support and move respective nozzles of a multi-nozzle.